The equation shown in the image is:

$L_2 = L_1 + 20 \log \left( \frac{r_1}{r_2} \right)$

This formula appears to relate to sound pressure levels or signal strength, often used in physics or engineering, particularly in acoustics or telecommunications.

• $L_1$ and $L_2$ represent the sound levels (or signal levels) at two different points.
• $r_1$ and $r_2$ represent the distances from a source to the measurement points.
• The logarithmic term is typically used in decibel calculations, where the change in sound or signal level is a function of the ratio of distances.

The factor of $20$ in front of the logarithm suggests that the equation is dealing with sound pressure levels or other phenomena that depend on the square of a quantity (e.g., sound intensity), as opposed to energy levels (which would use $10 \log$).

Would you like further explanation on this formula or its applications?

Here are 5 related questions for further exploration:

1. How is this formula used to calculate sound levels at different distances?
2. What is the significance of using logarithms in this context?
3. How would you apply this formula to find $L_2$ if $r_1$ and $r_2$ are given?
4. How does this formula relate to the inverse square law for sound intensity?
5. What other fields use similar logarithmic formulas?

Tip: Always remember that logarithmic equations like this are useful when dealing with quantities that change exponentially, such as sound intensity over distance.